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WAKA RESP
RESP
Inspiratory muscles contract; diaphragm descends and rib cage rises | |
During inspiration, thorasic cavity volume increases | |
During inspiration, lungs are stretched; intrapulmonary volume increases. | |
During inspiration, intrapulmonary pressure decreases to -1mmHg | |
During inspiration, air (gases) flows into lungs down its pressure gradient until intrapulmonary pressure is 0 (or equals atmospheric pressure) | |
As the external intercostals contract ribs elevate and sternum flares | |
Diaphragm moves inferiorly during contraction | |
Simultaneous movement of inspiratory muscles increase vertical and horizontal volume. | |
During expiration, inspiratory muscles relax (diaphragm rises and rib cage descends due to gravity. | |
During expiration, thorasic cavity volume decreases | |
during expiration, elastic lungs recoil passively; intrapulmonary volume decreases | |
During expiration, intrapulmonary pressure rises to +1mmHg | |
During expiration, air (gases) flow out of lungs down its pressure gradient until intrapulmonary pressure is 0 | |
During expiration, ribs and sternum are depressed as external intercostals relax | |
During expiration, diaphragm moves superiorly as it relaxes | |
Respiration is an intracellular process in the mitochondria | |
Forced expiration is an active process involving internal intercostal muscles and abdominal muscles | |
Inspiration is an active process | |
THE NERVOUS SYST. AUTOMATICALLY ADJUSTS THE RATE OF ALVEOLAR VENTILATION ALMOST EXACTLY TO THE BODY'S DEMANDS, THUS ARTERIAL PO2 AND PCO2 ARE HARDLY MODIFIED EVEN WITH MODERATE TO INTENSE EXERCISE OR OTHER RESP. DISTRESS. | |
THE RESPIRATORY CENTER IS COMPOSED OF SEVERAL GROUPS OF NEURONS LOCATED BILATERALLY IN THE BRAIN STEM OF THE CENTRAL NERVOUS SYSTEM (CNS) SPECIFICALLY AT THE MEDULLA OBLONGATA AND PONS. | |
DORSAL RESP. GROUP: DORSAL PORTION OF MEDULLA OBLONGATA. MAINLY INSPIRATION. MOST IMPORTANT COMPONENT OF VENTILATION | |
VENTRAL RESP. GROUP: VENTROLATERAL PORTION OF MEDULLA. INSP. OR EXPIR. DEPENDING ON THE NERVES STIMULATED | |
PNEUMOTAXIC CENTER: DORSALLY LOCATED IN THE PONS. RATE AND PATTERN OF BREATHING | |
THE MOST IMPORTANT ROLE IN CONTROLLING RESP. IS PLAYED BY THE DORSAL RESP. GROUP WHICH RECEIVES INFORMATION FROM THE CHEMORECEPTORS, BARORECEPTORS AND OTHER RECEPTORS IN THE LUNGS THAT HELP IN THE CONTROL | |
THE SIGNAL TRANSMITTED TO THE PRIMARY INSPIRATORY MUSCLES (DIAPHRAGM AND EXTERNAL INTERCOSTALS) IS A RAMP SIGNAL WHICH STARTS FROM 0 AND CONTINUES WITH A STEADY INCREASE FOR ABOUT 2 SECONDS. | |
RAMP SIGNAL STOPS FOR 3 SECONDS AND STARTS AGAIN THUS CAUSING A STEADY INCREASE IN THE PULMONARY VOL. DURING INSP. INSTEAD OF INSPIRATORY GASPS. | |
THE DURATION OF EXPIRATION IS DETERMINED BY THE DURATION OF INSPIRATION. | |
THE PNEUMOTAXIC CENTER LIMITS THE DURATION OF INSPIRATION AND INCREASES THE RESPIRATORY RATE. | |
STRONG SIGNALS FROM THIS CENTER REDUCE THE TIME OF INSPIRATION WHILE WEAK SIGNALS INCREASE the time of inspiration. ` | |
THE VENTRAL GROUP IS MOSTLY INVOLVED IN INCREASED LEVELS OF VENTILATION | |
THE ULTIMATE GOAL OF RESP. IS TO MAINTAIN PROPER [H+, [O2] AND CO2 IN THE TISSUES, SOMETHING ACHIEVED BY THE RESP. ACTIVITY. | |
H+ AND CO2 DIRECTLY STIMULATE THE RESP. CENTER CAUSING INCREASE OF THE INSPIRATORY AND EXPIRATORY SIGNALS. | |
O2 DOESN’T HAVE A DIRECT EFFECT ON THE CENTER BUT ACTS THROUGH THE PERIPH. CHEMORECEPTORS LOCATED IN THE CAROTID AND AORTIC BODIES. | |
AFTER FRESH O2 GETS TO THE ALVEOLI, THE NEXT STEP IS ITS Passive transport DIFFUSION INTO THE PULMONARY BLOOD AND CO2 IN THE OPPOSITE DIRECTION. | |
THE NET DIFFUSION OF A GAS IN ONE DIRECTION IS A DIRECT EFFECT OF ITS CONC. GRADIENT” | |
PRESS. AGAINST A SURFACE IS CAUSED BY THE CONSTANT IMPACT OF KINETICALLY MOVING MOLECULES AGAINST THAT SURFACE THE TOTAL PRESS. OF A GAS IS DIRECTLY PROPORTIONAL TO THE CONC. OF THE GAS MOLECULES | |
IN THE CASE OF RESP. PHYSIOLOGY WE DEAL WITH MIXTURES OF GASES (O2, CO2, N2). | |
THE RATE OF DIFFUSION OF EACH OF THESE GASES IS DIRECTLY PROPORTIONAL TO THE PRESS. CAUSED BY THIS GAS ALONE, KNOWN AS THE PARTIAL PRESSURE OF THE GAS. | |
EACH GAS CONTRIBUTES TO THE TOTAL PRESS. IN DIRECT PROPORTION TO ITS [ ] | |
GASES DISSOLVED IN H2O OR THE BODY TISSUES ALSO EXERT PRESSURE BECAUSE THE DISSOLVED MOLECULES ARE MOVING RANDOMLY AND HAVE KINETIC ENERGY. | |
THE PRESSURE OF A GAS IN A SOLUTION IS DETERMINED NOT ONLY BY ITS CONC. BUT ALSO BY THE SOLUBILITY COEFFICIENT OF THE GAS | |
THE PARTIAL PRESS. OF EACH GAS TENDS TO FORCE MOLECULES OF THAT GAS INTO SOLUTION, FIRST IN THE ALVEOLAR MEMB. AND THEN IN THE BLOOD OF THE ALVEOLAR CAPILLARIES. | |
THE RATE AT WHICH THEY ESCAPE FROM ONE MEDIUM TO ANOTHER IS DIRECTLY PROPORTIONAL TO THEIR PARTIAL PRESSURE IN THE BLOOD. | |
THE NET DIFFUSION IS DETERMINED BY THE DIFFERENCE BETWEEN THE TWO PARTIAL PRESS | |
THE NET DIFFUSION OF GASES THROUGH FLUIDS IS CAUSED BY PRESS. DIFFERENCE. | |
THE GAS PRESS. DIFFERENCE BETWEEN TWO AREAS IS KNOWN AS PRESSURE DIFFERENCE FOR DIFFUSION. | |
ALVEOLAR AIR IS ONLY PARTIALLY REPLACED WITH EACH BREATH | |
O2 IS GOING TO THE BLOOD | |
CO2 IS COMING FROM THE BLOOD | |
DRY ATMOSPHERIC AIR THAT ENTERS THE RESP. PATHWAYS IS IMMEDIATELY HUMIDIFIED EVEN BEFORE REACHING THE ALVEOLI | |
Va/Q = 0 cannot oxygenate the blood. | |
Va/Q = capacity for ventilation for this is area is infinity, but no gas exchange can occur. | |
AT EITHER 0 OR infinity RATIO, NO GAS EXCHANGE EXISTS. |